1. Field of the Invention
This invention relates to a method and an apparatus for constructing a building unit, more particularly to a method and apparatus for constructing an upper building unit on top of a pre-formed lower building unit by providing positioning pegs on the lower building unit so that the positioning pegs project upwardly from the concrete floor structure of the upper building unit when the latter is formed, and by mounting a wall form assembly on the projecting portions of the positioning pegs for forming the wall structure of the upper building unit without the need for waiting for a long period of time to allow hardening of the concrete floor structure of the upper building unit, thereby shortening the working period of the forming operation.
2. Description of the Related Art
In recent years, conventional forming operations for constructing concrete structures by nailing together wooden panels and pouring concrete between the wooden panels have been replaced by forming operations using modular steel form assemblies which permit efficient and high-quality construction of concrete structures and which result in savings in labor costs.
Conventionally, a building structure having a plurality of layers of building units, each of which includes a horizontal floor structure and at least one upright wall structure, is constructed in sequence by forming an upper building unit on top of upright wall structures of a lower building unit after the lower concrete building unit has hardened. Referring to FIGS. 1 and 2, a conventional modular form assembly 1 is shown to include a plurality of horizontal transverse and longitudinal girders 10, 11, a horizontal floor form panel 12 disposed on top of the girders 11, 10, and an upright wall form assembly 13. During construction of the concrete building units of the building structure, the modular form assembly 1 for an upper building unit is disposed on top of the upright concrete wall structures 15 of a lower building unit after the concrete wall structures 15 and the floor structure 14 of the lower building unit have hardened. In operation, positioning seats 16 are fastened to upper end portions of the concrete wall structures 15 and are spaced apart from one another. The transverse and longitudinal girders 10, 11 are mounted on the positioning seats 16. Then, the floor form panel 12 is disposed on top of the girders 11, 10, and the associated reinforcing bars and plumbing members are installed on the floor form panel 12. Thereafter, concrete is poured onto the floor form panel 12 and is allowed to harden after a waiting period of about 18 to 36 hours to form a concrete floor structure 17 with a sufficient strength. After the concrete floor structure 17 has hardened, an inner mold of the wall form assembly 13 is disposed on the concrete floor structure 17 at a predetermined position, and an outer mold is disposed around the inner mold and the floor structure 17 to confine a concrete pouring space. Associated reinforcing bars and plumbing members are installed on the wall form assembly 13 within the concrete pouring space before concrete is poured into the latter to form the wall structure. After waiting for another period of time to allow hardening of the concrete wall structure, the above procedures are repeated for constructing a further upper one of the building units.
Therefore, during construction of the building structure, a relatively long period of waiting time is needed to allow each of the floor structures and the wall structures to harden so as to impart sufficient strength to the same. The working period is generally overly long and cannot be shortened. This problem becomes more severe when constructing a building structure which has identical building units at different sites. Due to the insufficient space in the work place of the building structure, a single formwork is usually employed at different sites in an alternate manner for constructing the building units. This is achieved by advancing the operating procedure in a site (A) to the operating procedure in another site (B) for a work stage. That is, when the concrete wall structure formed in the site (A) has hardened, the wall form assembly is detached therefrom for use in the site (B) for constructing the same concrete wall structure therein. However, that the wall form assembly used in the site (A) cannot be detached until the concrete floor structure formed in the site (B) has hardened, which usually takes a long period of time. As such, a relatively large part of the working period is spent waiting for the concrete floor structures to harden during the construction of the building units.